Flue-unblocking and safety system for incinerators



/7 :L /8 "if? l June 2, 1953 J. K. BLUM 2,640,447

FLUE-UNBLOCKING AND SAFETY SYSTEM FOR INCINERATORS Filed June 19, 1950 RELAY L INVEN TOR. JOSEPH K. BLUM BY W YM Patented June 2, 1953 FLUE-UNBLOCKING AND SAFETY SYSTEM FOR INCINERATORS' Joseph K. Blum, Scarsdale, N. Y., assignor to Burnwell Incinerator Corporation, New York, N. Y., a corporation of New York Application June 19, 1950, Serial No. 168,949

11 Claims.

This invention relates to incinerators and has particular reference to a novel system for unblocking the feeding chute of an incinerator by releasing the matter wedged in said chute, and for giving a warning that such a blocked condition exists.

The invention relates particularly to the single flue type of incinerator, in which the single flue serves both as a feeding chute through which refuse is dropped, and a gas discharge flue. Incinerators of this type used in multiple dwellings generally consist of a flue or chute, about three to four square feet in cross-section, which extends from the basement of the building to the roof. At each floor, a feeding door is provided for depositing refuse into the chute, through which it drops into the incinerator furnace in the basement. This refuse is burned when the furnace is fired, the hot gases and smoke being drawn up the flue.

One of the problems encountered in the use of incinerators of this type is the frequent clogging of the flue by refuse which becomes lodged therein. Although the feeding doors are usually designed to restrict the size of the rubbish fed into the chute, they are not always effective in preventing clogging. For instance, a folded box may open up in its descent through the chute and become wedged therein. When this occurs, gases and smoke from the incinerator furnace are forced out through the access and feed openings of the furnace, as well as through the; feeding doors of the chute, causing a considerable nuisance as well as possible danger.

When such clogging is detected, it is the usual practice either to ignite the clogged refuse and allow it to burn out, or else to drop a weight of some sort down the chute, which will forcibly release the blocked matter. Both of these remedies are performed manually, requiring the lapse of considerable time before the remedy becomes effective. In addition there is usually an appreciable time delay involved in discovering a blocked condition of the chute. It is therefore desirable that immediate notice of such a condition be given, and a remedy therefor applied quickly.

I therefore provide an unblocking system which includes means operatively responsive to an increase in gas pressure within the incinerator furnace or adjacent feed flue, said means being adapted to actuate an unblocking mechanism associated with the chute, and being also adapted to actuate suitable warning signals, lock the incinerator feeding doors, and/or halt the operation of auxiliary mechanism of the incinerator.

It is an object of the invention to provide an unblocking system of the type described in which operation of the mechanism is begun automatically as soon as the draft in the incineratoris decreased appreciably by a clogged condition of the chute.

Other objects and advantages of the invena tion will be readily apparent in the course of the following specification when taken in connection with the accompanying drawing, which 11- lustrates a preferred embodiment of the inven tion.

of a chute unblocking and warning system as applied to a flue-fed incinerator of the single flue type. The incinerator furnace and flue are shown in side elevation and are partially broken away to reveal the inner construction thereof.

Referring to the drawing, the incinerator generally comprises a furnace l, and a flue 2 which opens into the top of said furnace I. Flue 2 ex-' tends vertically the height of the building in which the incinerator is installed, and extends through the roof of the building as a chimney. The flue 2 serves the combined function of 'a gas discharge flue and feeding chute. For the latter purpose, a feeding door 3 of the usual type is provided at each floor of the building, these doors 3 being located vertically, one above the other. For convenience, only one of these feeding doors 3 is illustrated in the drawings. When the occupant of an apartment wishes to dispose of garbage or rubbish, he opens the respective feeding door 3 and dropsthe refuse down the flue 2 into the furnace l.

The furnace I has an upstanding partition wall 4 which forms a refuse-accumulating chamber I a at one end of said furnace. A grate 5 is secured to the partition wall 4 and the end wall of furnace l, across the refuse-accumulating chamber la, and in parallel, spaced relationship to the floor of said chamber la. The flue 2, communicates with the interior of furnace I above chamber la, so that when refuse is dropped down flue 2, said refuse R will land upon grate 5, and accumulate thereon.

The furnace I may also be provided with an externally-located fuel burner 61;, such as an oil burner or gas burner, whose nozzle 6 extends within the interior of the furnace I. When the burner 6a is fired, the flame discharged by nozzle 6 covers the refuseaccumulating chamber Ia so that this flame assists in the drying and burning of the refuse R accumulated on the grate 5.

A by-pass flue I communicates with the end The drawing shows a partially schematic view of the furnace I opposite the refuse-accumulating chamber Ia. This by-pass fiue I communicates with the main flue 2 adjacent the bottom of said flue 2. The furnace I may also have auxiliary blowers 3G or fans 3| to introduce a stream of -air within the flue 2 or by-pass flue I in such a manner as to cause the gases generated by the burning refuse R to be caused to leave the furnace I through the by-pass flue I instead of rising directly up the flue 2. Such an arrangement is fully described in co-pending U. S. patent application, Serial No. 137,352, filed January 7, 1950, of which -I am a co-inventor. The operation of these blowers or fans forms no part of the present invention, except insofar as their operation may be regulated by the control means of the unblocking unit.

The furnace I contains the usual access or feed openings 8 which have doors which may be opened or closed when required in order to regulate the draft, permit the removal of ashes, enable refuse to be deposited in the furnace from the basement, etc.

.It-is to be understood that the invention herein is not to be limited to any specific type of incinerator or furnace. The incinerator illustrated in the drawing is shown by way of illustraltion only, and any other standard type of incinerator furnace maybe substituted in its place.

As was previously indicated, if refuse should become wedged in the flue 2,, while the refuse Ris burning in the furnace I, an annoying and dangerous situation will arise. The clogged condition of the flue 2 will, in most instances, decrease the drawing action of said flue 2, and may even prevent the hot gases and smoke from furnace I from rising through the length of flue 2 to the chimney at the roof. The gases and smoke become trapped in. the flue 2, causing a marked reduction of the draft in furnace I, and possibly a definite positive pressure. The gases and smoke, being prevented, or substantially prevented, from escaping through the chimney, seep through the feeding doors 3 of the-flue 2, below the clogged area, and through the access :doors 8 of furnace I. As a result, the basement, as well as the hallways or apartments located belowthe clogged area, become filled withsmoke and fumes. In addition, sparks, or even .fiame, are likely to escape through the feeding doors 3 or access doors 8 if these doors are opened while the clogged condition exists.

To remedy this clogged condition at its outset and before serious damage or annoyance can occur,.I provide an automatic unblocking or dueclearing system which may be incorporated in the .incinerator. 'This system comprises a pressure-responsive unit which actuates a mechan'i'sm for dropping weighted objects down the flue 2 and at the same time actuates suitable signal devices or other mechanisms associated with the incinerator.

'The'pressure responsive unit includes a hollow tube I0 which extends within the interior of furnace I and communicates with a sensitive pressure-operated relay unit P located outside the furnace "I. The tube I0 is so located within furnace I that any change in pressure within said furnace will be transmitted to the pressureoperated relay unit P.

The pressure operated relay unit P includes a.,-pressu're responsive control member I3 which controls one or more electrical switches 26 and 21 which regulate-electrical current through lead wires II and I2. This current is supplied from a suitable power line through leads Na and I2a.

The pressure responsive control member I3 may be a pressure sensitive diaphragm of the conventional type which is used in connection with draft regulation in boilers and furnaces although other types of conventional type pressure operated controls may be used. The diaphragm I3 is operatively connected by a bar I3a with one or more electrical switches and is pre-set to close said switches when the diaphragm I3 changes position as a result of an increase in pressure within furnace I, and to open said switches when the diaphragm returns to its pre-set position, thus energizing and deenergizing the relay P.

'I'pre'ferto employ a pair of mercury switches 26 and 2] of conventional and well-known type which are arranged in such a manner that one switch closes the electrical circuit at one position of the diaphragm and the second switch opens the electrical circuit at a different position or degree of movement of the diaphragm. For example, the mercury switches 26 and '21 may be pivotally mounted as shown in the drawing and may be bracketed by depending pairs of fingers I3b and'l3c of the bar I3a. The pair of fingers I3b are spaced apart a greater distance than the fingers I30 so that the switch '26 is returned to its original open position before the switch 21. This mercury switch arrangement is conventional, and no claim .is made to the same in itself. Actually, a single electrical switch might be used effectively, except that under certain conditions the equipment controlled by the flowing of current through wires I I and I2 might be energized and dc-energized several times in rapid succession due to rapid variation of draft conditions in the furnace, causing damage to the equipment. If, however, the pressure operated diaphragm I3 or the relay P were so constructed to provide a delay in time between the opening of the circuit and the closing thereof, a single switch may be effectively used without damage to the equipment.

The wires II and I2 lead to a dumping device I i located adjacent the top of flue 2. This'dumping device I4 is situated above the top-most feeding door 3 of flue 2, and is preferably on or adjacent to the roof of the building. The dumping device I I comprises an endless belt I5 mounted on rollers I6, one or both Of which is driven by an electric motor M. The wires II and I2 are connected to this motor M. A hopper or feeder I'I or other feeding device is mounted above the endless belt I5, saidihopper I'I contain ing weighted articles A such as bags of coal, sandbags, rocks, stones, or the like. The wall of flue 2 contains an opening I8 adjacent the endless belt I5, so that when said endless belt is driven toward said opening, the weighted articles fed by hopper II on said endless belt I5 are dropped through the opening I8. The dumping device described is of simplified design. Many other types of dumping devices of conventional design would work "equally well.

One or more warning devices or the like may be connected across lead wires I9 and 26, said wires I9 and 20 being connected to respective wires II and I2. As a result, these warning devices are connected in parallel with the motor .M of the dumping device I l. The warning devices may consist of a bell or buzzer '2I and a signal light 22. In addition, electrical locking devices 23 on each of the feeding doors 3 may be connected across wires I9 and 26, so that when 'cur-- rent is passed through wires I9 and the feeding doors 3 are locked in closed position.

Any auxiliary equipment used in the operation of the incinerator, such as the fans 3|, blowers 30, etc. previously described, and also the auxil-,

iary burner 6a which discharges flame through nozzle 6, may be connected to a second power line by wires 28 and 29 whose current is controlled through a second relay L. This second relay L may be of the conventional solenoid type and is connected across power line II, I2 by means of respective lead lines 24 and 25. Current flows through the leads 28 and 29 to the auxiliary equipment in the normal operation of the. incinerator. When the circuit is closed through leads II and I2, and 24 and due to a clogged condition of flue 2, the relay L is actuated, breaking the circuit of leads 28 and 29, and causing the auxiliary equipment to be shut off. Ordinarily, during the burning operation of the furnace I, a draft is induced in the furnace I and flue 2. This draft creates a negative pressure within the furnace I. When refuse becomes wedgedwithin the flue 2, the draft is decreased so'that the pressure within furnace I is increased. If the flue 2 becomes completely clogged, a positive pressure may, build up within the furnace I. Draft conditions vary in different incinerator installations depending upon the type of furnace,

length of flue, surrounding atmospheric conditions, and many other factors. In a particular installation, however, it is possible to ascertain by measurement the average draft or at least the range in which the draft will vary under normal conditions. Accordingly, the mercury switches 26 and 21 controlling the current through wires II and I2 may be set so that they will be actuated by diaphragm I3 when the draft within the incinerator I decreases below the minimum normal endless belt I5 in a direction to deposit theweighted articles A in the opening I8 of chute 2.

Simultaneously, the circuit is closed through wires I9 and 20, causing the bell or buzzer 2| to ring, the signal light 22 to ignite, and/or the locking means 23 to lock the feeding doors 3. The bell 2I or signal light 22 may be located at a convenient place in the building at which it can notify the building attendant immediately upon congestion of the flue 2. In place of the locking means 23, similar warning buzzers, bells, or lights may be placed at each floor near the feeding door 3 to warn the occupants of the building not to open the feeding door while the flue is blocked.

The circuit is also closed through wires 24 and 25, causing relayL to break the circuit through leads 28 and 29, shutting off the auxiliary equipment, if any.

When the weighted articles A are inserted in the flue opening I8 by the dumping device I4,

these weighted articles will drop down the flue 2 and strike the refuse'wedged in said flue 2. The momentum and weight of the articles A force the refuse free of its wedged position, the dumping device I4 continuing to operate until the refuse is freed and falls into the furnace I. When the flue 2 becomes unblocked, it again begins to draw, and the draft within the incinerator is again built up to normal. This pressure change is transmitted to the diaphragm I3, so that said diaphragm I3 may again take its normal pre-set condition, opening the mercury switches 26 and 21 terminating the operation of the dumping device I4 and of the warning and locking devices. The auxiliary equipment is also re-actuated.

As a practical example, the normal average draft in a specific incinerator installation may be .20 inch of water, and the draft variation range under normal conditions may be between .50 inch and .06 inch. The mercury switches 26 and 21 may therefore be set to close simultaneously when the draft in the incinerator falls below .02 inch, it being a safe assumption that at this point the draft decrease is not caused by natural phenomena, but rather by a clogged condition of the flue. The Warning signals and the unblocking mechanism are therefore actuated when the draft drops below the minimum limit of .02 inch, and the auxiliary equipment of the incinerator is de-actuated. When the clogged condition of the flue has been corrected, the draft will again increase. One of the switches such as the switch 2! is, however, pre-set to open only when the draft increases toward its average reading, for example to 08inch. At this,

point, the switch 21 will open, the warning sig nals and unblocking mechanism will be de-actuated, and the auxiliary equipment will again be actuated.

In some installations because of unnatural or unusual draft conditions, the draft in the furnace or flue may momentarily drop below the pre-set minimum level previously described even though a clogged condition of the flue does not exist. In such an instance, it is desirable to prevent the unblocking mechanism and warning signals from being actuated, and to prevent the auxiliary equipment from being de-actuated.. In this type of installation, therefore, a timedelay mechanism T may be provided to prevent the relay P from actuating any of the control units unless the decrease of draft in the incinerator has continued for an appreciable length of time. Such a time delay mechanism may be of any of the conventional types, and may be an electrical.

control incorporated in the circuit, such a bimetal switch 32 or the like in the line II which is proximate to a heater coil 33 connected across lines II and I2. When the bi-metal switch 32 is heated by the coil 33, it closes the circuit through line II.

In addition, draft conditions in some installations may be such that the draft decreases below the pre-set minimum level in the absence of a blocked condition, while the incinerator is not ment through a hydraulic or pneumatic circuit.

which may be adapted to produce the desired results, namely to indicate that the flueis clogged, to shut off any auxiliary equipment, and to free the-flue of the clogged matter.

The operation assume 71 on hydraulic and: pneumatic; systems. are well;- known; and neednot bedescribed in detail.

While.- preferred embodimentsv of the invention. hailebeen shown and described herein, it: is obvious: that numerous additions, alterations, and omissions may be made; inthe invention without departing, from the spirit: and scope thereon.

Lolaim;

I, In combination with. an: incinerator of thecharacter: described comprising a furnace and a single. upright flue: communicatingwith the top ofrsaid furnace; said flue; serving as both; a gas discharge flue-and.- feeding: chute, an; unblocking system. adapted to dislocate; automatically refuse: lodgedain said flue, said system. comprising normally dormant. dumping. means communicating with; said flue adjacent: the" upper endthereof and adapted to introduce weighted material in said. flue upon actuation, a pressure sensitive element communicating with the interior ofsaid furnace and being responsive to increases of pressurein-said incinerator: due to a clogged condition. of the flue, and: means responsive to: said element for actuating said dumping means.

21 In combination with an incinerator ofthe character described comprising a furnace and a single upright fluecommunicating with: the. topof" said furnace, said flue serving as both a gas discharge flue and feeding chute, an unblockingsystem adapted to dislocate automatically: refuselodged in said'fiue, said system comprising nor-- mally dormant dumping means communicating; with said flue adiacent the upper end thereof. and: adapted to introduce weighted materialv in. said flue upon actuation so that the weighted material falls through said flue,v a'pressure sensitive element communicating with. an interior: portion. of saidincinerator other than; said flueand being responsive to. changes of. draft within. said incinerator, andimeans. responsive to said. element operatively connecting said element and said dumping-means for actuation of said dumplug-means, said connecting means being: pre-set. to: actuate said: dumping. means when. the: draft: within incinerator isreduced. below a first se.-- lected limit. due to. a clogged condition of said. flue; and. to tie-actuate said dumping meansgwherr thedraftvwithin said incinerator increases alcove: a second selected limit.

3. In combination with an incinerator of; the;

character described comprising; a. furnace. and a. 0

single upright flue communicating with; the. top, of -said furnace, said flue serving. as. both. a gas: discharge flue and feeding chute and: having: at; leasti one feeding door, an, unblocking; and safe.-

tyrsystem; adapted to dislocate automatically re-i fuse lodged in said flue, and to prevent. 0pera-,-. tion and use of the incinerator. during: a clogged condition. thereof, said. systemcomprising, normally dormant; dumping means con'irnunicating:v with saidflue adj acent, the-upper endthereof. and: adapted to. introduce weighted material. in said flue; upon. actuation so that the weightedv marterial-- falls through said flue, warning, signal. means located exteriorly. of said incinerator, a. pressure-sensitive element communicating with aninterior portion of said incinerator-other than saidfiufi and-being responsiveto changesof draft. within;saidaincinerator, and means; responsive to; said; elementoperatively connecting said element to. .said dumping means and. Warning. signal." means; for actuation thereof, said connecting means- 11e,- ing= pre-set; toactuate; said; dumping. means; and warning: signalmeansawhen; the draft; within said;

8?. due toa' clogged: condition: of said" flue; and" to: desactuate said dumping and warning; signal means when the draft within: the. incinerator in creases. above? asecond selected-limit;

4. An unblocking'and safetysystem: according; to claim 3' in which; each feeding door-oi. the; iii-- cinerator is provided with a lock, and-themes sure= sensitive means is: operatively: associated, with; said: lock: to lock said loclcautomatically;-

. whenrthedraft. in said. incinerator'is reduced-Me lowa said first selected: limit, andz-unloclc'saidloclc when the draft increases abovesaid second .89? lected limit;

5-. In combination with-:an incinerator having:

' a furnace and. asingle: upright'iflueg communicat.

, tion, and'to release saidmaterial within saidaflue;

to clear said flueof cloggedmatter-therein, warn ing signal means, and safetymeansto prevent, further operation of" the incinerator, means res. sponsiveto said pressure sensitive unit operativelyconnecting said 'unityto.1said-'- dumpingt warn-- ing; and safety" means: for simultaneous; actua-.. tion thereof, said connectingmeansbeingprefect: to actuate said dumping, signal; and; safety means when the-pressure'with-in said-incinerator: increases: above a first selected-limit due to. GA clogged condition of said flue; andi= to d'e-actuatev said dumping; signal; and safety meansc when the pressure within the incinerator" decreases below a" second selected limit;

6 A controlsystem according to: claim 5 in: which the incinerator has auxiliary firing equip ment and the incinerator flue has: at. least: one feeding door, said safety means including a lock: onsaid feeding door which is-normally'unlocked': duringoperation ofthe incinerator and means; to shut off said: auxiliary firing equipmentand; lock said lock when: the pressure: wit-himsaid; in-i cinerator increases above said first; selected;

limit;

'7; Incombination with an incinerator having; a-

' furnace and a single: upright flue: which serves;

both asa gas discharge-- flue and feedingr chute communicating with the A top: of said: furnace; an unblock-ingsystemadaptedto automatically diselocate-refuse lodged in said flue, said system com? prising normally dormantdumpingmeans= comelug-normally opento interruptthe: flow; off-cunrent to:-said dumping: means; and pressure: SE11?! sitivemeanscommunicating with the: interionof said furnace: and being responsive; to; chains-c3501? draft within said incinerator, said pressure 58115.12"

tive mea'ns being operatively associateduwithsaid switch means. to close; said: switch... means: when therdraftywithin said 1 incinerator decrcasesgbelovr a selected limit due to a clogged condition of- 8. unblock-mg system according. to claimfl: in which. said electrical, circuit also. includes warning signalmeans, located exterior-1v; of said inoineratorv which. are. operated whenv thetswitchincineratoris reduced below. a; first.- selected-limit; 7 means area-v closed;

9. In combination with an incinerator having a furnace and a single upright flue which serves as both a gas discharge flue and feeding chute and communicating with the top of said furnace, an unblocking system adapted to automatically dislocate refuse lodged in said flue, said system comprising normally dormant electrically operable dumping means communicating with the interior of said flue adjacent the upper end thereof and adapted to discharge weighted material down said flue, an electrical circuit connecting said dumping means to a source of electric current for actuation thereof, switch means interposed in said circuit and being normally open to interrupt the flow of current to said dumping means, and a pressure sensitive diaphragm which communicates with the interior of said furnace and is responsive to changes of draft within said incinerator, said diaphragm being coupled to said switch means for closing said switch means when the draft Within said incinerator decreases below a first selected limit due to a clogged condition of the flue, and for opening said switch means when the draft within said incinerator increases above a, second selected limit.

10. In combination with an incinerator having a furnace, a single flue which serves as both a gas discharge flue and feeding chute, and an auxiliary fuel burner, said flue and auxiliary burner being operatively associated with said furnace, a control system comprising a pressure sensitive unit communicating with the interior of said furnace and being responsive to pressure changes within said furnace, and control means regulating the operation of said auxiliary fuel burner, said pressure sensitive unit being operatively connected to said control means whereby said auxiliary burner is de-actuated when the draft Within the furnace is decreased to a pre-set level, below the normal draft range of the incinerator due to a clogged condition of said flue.

11. A control system according to claim 10 in which the pressure sensitive unit is adapted to actuate said fuel burner when the draft within the incinerator increases to a pre-set level within the normal draft range of the incinerator.

JOSEPH K. BLUM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,645,262 Treganowan Oct. 11, 1927 2,114,257 Thomas Apr. 12, 1938 2,161,412 Gregg June 6, 1939 2,168,004 OHara Aug. 1, 1939 

